Accidental pvp

I may have mentioned that I hate pvp . Rift tries it's hardest to make me do it tho.
I was playing a sab, which for those of you not playing one, involves placing charges on the enemy mobs and then exploding them. You can also place a ring of mines round yourself so that when the mob approaches, they get hit by another blast.
I'd carefully set up my charges and mines ready to attack a particular mob, when a guardian rode by (I was playing Defiant) and blew themselves up on my mines. That apparently was enough to mark me as pvp cos he then attacked and killed me! Sigh.
I've since discovered there's a setting which will help me avoid that, but at the time I was incensed at the unfairness of it all (lol).

ROFL...

Had a similar accident yesterday, both sides were busy during an invasion, and I tabbed mid fight onto a Guardian trying to target another mob, and dead!

No message that attack will flag you PvP??
And how do "human controlled" Guardians differ in appearence from NPCs at in invasions?
Could this happen in every zone?
Gah, I hate PvP...